1. Field of the Invention
The present invention relates to rolling bearings that receive high static load of a wind turbine generator and a wind turbine generator using the rolling bearings.
2. Description of the Related Art
A wind turbine generator generally consists of a rotor hub to which blades for receiving the wind are connected, a rotation shaft for transmitting the rotation of the rotor hub to a generator side, a tower, and a nacelle for housing the rotation shaft, the generator and the like.
In the wind turbine generator, a variety of rolling bearings are used such as bearings for supporting a nacelle base such that the nacelle base can swivel, and bearings for supporting the blades such that the pitch of the blade can be adjusted.
This wind turbine generator is exposed to weather such as a strong wind, and thus the rolling bearings are subjected to high load. Further, from a perspective of efficient power generation, it is encouraged to make larger wind turbine generators and the load on the roller bearings of the wind turbine generator gets higher.
To take measure against such high load, Patent Document 1 proposes a roller bearing having an inner ring, a center ring, and an outer ring for supporting the blades such that the pitch of the blades can be adjusted. In the rolling bearing, the center ring to which the blade is fixed is supported from both surfaces thereof by the inner ring and the outer ring so that the high load on the rolling bearing is diversified.